Vehicle power window systems use a reversible electric motor to open and close an associated window. Typical systems include a bi-directional window switch electrically connected to the reversible electric motor. The motor is operatively connected to an opening and closing mechanism attached to the associated window. When the switch is manually operated and held in position by a vehicle occupant, electric current is supplied to the motor causing the motor to rotate in a desired direction. When the motor rotates, the opening and closing mechanism opens or closes the window. When the window switch is released, the motor rotation stops and the window movement stops.
Some power window systems have an automatic operation feature. In an automatic operating mode, a single movement and release of the window switch causes the window to fully open or fully close even though the switch has been released. Some automatic mode power window systems include what is referred to in the art as an "anti-trap" feature. The anti-trap feature is designed to prevent closing of the window on an obstruction, e.g., part of an occupants body, and "trapping" the obstruction in the window. When the window is moving in an upward direction and an obstruction is encountered in the path of the window, a typical power window anti-trap system senses that an obstruction is resisting continued upward window movement. Upon detecting the increased resistance to movement, the anti-trap system reverses the window direction.